The invention relates to sealing flow-through cartridges, e.g., column chromatography cartridges, of variable effective length.
Liquid column chromatography is a technique for identifying, separating, or purifying individual components in a subject sample. In employing the technique, a "stationary phase," such as a surface active powder, is packed into a chromatographic column. A "mobile phase" consisting of a carrier liquid and a sample to be identified, analyzed, or purified is passed through the column. Different compounds in the sample migrate through the column at different rates, depending, e.g., on their size and degree of attraction to the stationary phase in the column. Consequently, the different compounds in the liquid emerge from the column at different times, allowing separation of the compounds in the sample. See U.S. Pat. No. 5,601,708 to Leavesley ("Leavesley"), and U.S. Pat. No. 4,250,035 to McDonald et al., both of which are incorporated herein by reference in their entirety.
Liquid column chromatography is often carried out using disposable cylindrical cartridges. The cartridges contain the stationary phase, or media bed, bounded axially on both ends by porous plates. The ends of the cartridges are often sealed at both ends above the porous plates by sealing assemblies. Column chromatography cartridges can have media beds of different lengths, which must be taken into account in designing systems for sealing cartridges.